Conventionally, in various processes performed on a substrate for manufacturing a semiconductor, a liquid crystal display device, an optical disk, or the like, a temperature regulator (a cooling device or a heating device) is used, in which a flow path for circulating a thermal medium for cooling or heating is formed inside a plate made of aluminum or aluminum alloy. Such a temperature regulator is formed such that, for example, two bulk materials to be used as an upper side and a lower side of the plate are prepared, the flow path is formed on each of the surfaces by a groove cutting process, and the surfaces of the upper side and the lower side of the plate where the flow paths are formed are brought into contact with each other and joined by brazing or the like. Because aluminum has good thermal conductivity, there is an advantage in that heat of the thermal medium can efficiently be transferred to the substrate via the wall of the flow path and the plate, and the temperature of the substrate can be regulated quickly and uniformly.
Meanwhile, because aluminum is a highly corrosive metal, a thermal medium that is available to the temperature regulator made of aluminum is limited. Therefore, water mixed with corrosion inhibitor (process cooling water: PCW), organic solvent, inert gas, or the like is exclusively used. However, in the industry, there is a demand to use, as the thermal medium, city water that can easily be available at low costs or seawater that can abundantly be available from natural resources.
To make the flow path resistant to corrosion, it may be possible to form a flow path portion with a corrosive metal or alloy. For example, Patent Literature 1 discloses a technology in which a cooling pipe made of copper having excellent thermal conductivity and corrosion resistance is installed inside the main body of a susceptor of a semiconductor manufacturing apparatus.